Apparatus for preventing condensation in gas mains



Feb. 27, 1940. KOLLE'R 2,192,011

APPARATUS FOR PREVENTING; CONDENSATION IN GAS MAINS Filed June 30. 1937EUKNEE I .WST SEPHPAWZ INVENTOR KARL KOLL ER Patented Feb. 27, 1940UNITED STATES APPARATUS FOR PREVENTING OONDENSA- TION IN GAS MAINS KarlKeller, Budapest, Hungary Application June 30, 1937, Serial No. 151,255

2 Claims.

This invention relates to the distribution of combustible gas containingcondensable materials, particularly producer, gas made in a produceremploying bituminous coal as the fuel.

In many plants, combustible gas containing tarry matter including taracids and other condensable constituents, e. g., producer gas generatedby blowing. air through a bituminous coal fuel bed, is cleaned bypassage through one or .more washing and grid chambers or other cleaningequipment and the resultant cleaned gas distributed through a pipingsystem to furnaces or other appliances where it is burned. In suchplants, reduction of the temperature of the gas between the cleaningequipment and the point of consumption causes condensation ofcondensable constituents such as tarry matter in the lines leading tothe burners, requiring frequent interruption of plant operations toclean the gas distribution conduits, meters, etc. Such interruptions, itwill be appreciated, result in loss of time and labor in cleaning thedistribution system and result in the formation of objectionable, denseclouds of smoke when the deposits of condensed material are burned toeffect their removal. Moreover, in many plants where producer and othercombustible gas is employed, the washing or scrubbing liquor from thegas washers contains tar acids, including phenols, and, therefore,cannot be discharged into streams. In many localities municipalordinances prohibit the discharge of such waste liquors into streams andwaterways. Hence, such waste liquors or ei'fluent present a difficultdisposal problem.

It is an object of this invention to feed or distribute combustible gascontaining condensable constituents such as producer gas made frombituminous coal in such manner that condensation of tarry material inthe gas line is-minimized or substantially completelyeliminated.

It is a further object to distribute combustible gas such as producergas as generated and without subjecting the same to water washingthrough the usual distribution systems in industrial plants so as toavoid objectionable deposits in such systems.

Other objects and advantages of the invention will appear from thefollowing description:

In accordance with the invention, I. introduce into the distributionsystem hot gases atatemperature and in amount such that the combustiblegas reaches the gas consuming appliances at a temperature above the dewpoint of the condensable materials therein. Preferably the combustiblegas is superheated to a temperature such that it reaches the appliancesat a temperature equal to or above the temperature of the gas enteringthe mains by burning a portion of the gas and conducting the hotproducts of combustion into the distribution system where it mixes withthe combustible gas. Thus heat losses from the system as the gas flowstherethrough are compensated by the hot gases added to the system,thereby preventing cooling of the gas to a point where substantialcondensation of the condensable'materials will occur. Accordingly,- inplants where the waste liquors present the hereinabove mentioneddisposal problem, water washing of the gas may be eliminated andcondensation of tarry and other condensable constituents within thedistribution system prevented by the practice of this invention.

The invention also comprehends apparatus for preventing condensation ofcondensable materials in a gas distribution system involving burnershaving combustion chambers communicating with the system, lines forsupplying air to the burners, lines for supplying combustible gas to theburners and mechanism for automatically terminating flow of gas and airto the burners when the gas pressure in the system falls below apredetermined minimum.

A preferred embodiment of the invention is shown for purposes ofexemplification in the accompanying drawing, wherein Fig. 1 is a view,somewhat diagrammatic in character of a gas distribution system equippedin accordance with the invention,

, Fig. 2 is a'view illustrating on an enlarged scale a portion of theapparatus of Fig. 1, and

Fig. 3 is a sectional view through a gas distribution main equipped inaccordance with the invention.

Referring more particularly to the drawing, reference'numeral 8indicates generally apparatus for producing combustible gas which mayinclude a producer containing an incandescent bed of bituminous coalthrough which air is blown upwardly, the resultant producer gas passingoff from the top of the producer through gas offtake l I. As is wellknown in the art, gas such as producer gas made from bituminous coalcontains objectionable impurities and is ordinarily subjected tocleaning operations such as scrubbing in washing and grid chambers whichresult in partial cleaning of the gas. The eilluent liquor from thescrubbers contains tar acids including phenols and hence present adifficult disposal problem.

In the embodiment of the invention shown in Fig. l, the gas from theproducer is passed not through scrubbers where it would be contactedwith water or other liquid, but through a mechanical dust collector suchas a cyclone separator l2. From this dust collector the gas isintroduced into distribution main i6 equipped with branches l8 and 28leading to burners 22 and 24 of furnaces 26 and 28 respectively. Theburners 22 and 24 are ordinarily located some distance from the dustcollector, as indicated by the broken mains connecting line l6 withfurnaces 26 and 28, so that the gas is subject to substantial reductionin temperature due to heat losses between the dust collector and thefurnaces. In order to avoid condensation of the tarry materials in thedistribution mains, particularly the branch mains leading to theburners, thereby clogging the mains, meters, etc. and necessitat ingfrequent shutdowns to clean out the mains, l have equipped thedistribution mains for the gas at suitable points with burners,designated generally by reference numerals 38 and 32 in Fig. 1 and shownin detail in Fig. 3.

Each burner includes a valved air inlet 34 connected to an air supplyline 35 equipped with a water seal 31 and combustible gas inlet 38connected to gas supply line 4| equipped with water seal 43, refractorylined combustion chamber 45, electric heating element 41 and perforatedflame spreader or distributor 48. The open end 6| of the combustionchamber projects into the gas distribution main, any suitable joint 63being employed to form a gas tight connection between the main andexterior of the burner. The water seals 31 and 43 prevent back flow ofair and gas through the lines supplying 86 and 4| respectively.

Gas supplied to the burners through supply line 4| may be clean gasavailable at the plant or may be bled off from the distribution system.For the latter purpose line 4| may be connected, e. g., to distributionmain l6 at any suitable point.

In Fig. 2 I have illustrated somewhat diagrammatically an automaticmechanism for terminating the flow of air and gas to the burners inevent the supply of combustible gas through the distribution main I6 isshut off or the pressure in the system for any reason falls below apredetermined minimum. The cutofl mechanism involves an air valve 68 ineach of the air inlet conduits 34 and a gas valve 62 in each of the gasinlet conduits 39 to the burners. The gas and air valves for each burnerare joined for simultaneous operation by connection 64 and each pair ofvalves 68, 62 is equipped with an operating lever 66 connected to cable68 through branch cables 18; cables 68, 18 nm over pulleys 12. Cable 68is connected at one end to a counter-weight 14 preferably constructed asa piston and sliding in cylinder 16 provided with an adjustable port 18.The piston and cylinder form in effect a dash pot to cushion the fall ofthe piston counter-weight upon release of the cable. 68 in a mannerhereinafter described. The other end of cable 68 is wound on drum 88equipped with ratchet 82 and manually operated handle 84. Detent 86 isrigidly connected at one end to lever 88 and the other end of the detentcooperates with ratchet 82. Lever 88 is pivotally mounted at 88 andequipped at one end with an adjustable weight 82. The other end of thelever is connected to bell 84 partially submerged in a body of liquid inbell tank 86. An extension 98 of gas line 4| terminates in anddischarges gas into the space beneath bell 34 so that the pressurebeneath the bell corresponds to the pressure in the gas line anddistribution system.

The operation of the device is as follows:

When gas is passing through the mains 6, 8 and 28 to burners 22, 24,electric current is sup plied to heating element 41 to heat it toincandescence and levers 62 are manually lowered to permit flow of gasand air to the burners 38, 32; the incandescent heating element ignitesthe mixture of gas and air. The amount of gas and air fed to the burnersmay be controlled by adjustment of valves 68, 62 and is preferably suchthat the products of combustion from the burners impart to the gasflowing through the distribution system superheat in amount suflicientto prevent the temperature of the gas from falling below its dew pointprior to reaching the burners. Upon drop of pressure in the distributionsystem, the pressure in line 4| and extension 88 also fails thus causinga drop in pressure beneath the bell 84. Air pressure forces the belldown causing rotation of lever 88 in clockwise direction about its pivotand raising of detent 86. When the pressure beneath the bell fails apredetermined amount, detent 86 is disengaged from ratchet 82 permittingweight 14 to unwind cable 68 from drum 88 and close air and gas valves68, 62 by raising levers 66. When it is desired to again start theburners in operation, cable 68 is wound on drum 88 by turning handle 84,detent 86 engaged with the ratchet 82 and valves 62, 68 set to permitflow of the desired amount of gas and air to the burners.

Preferably the burners are located in the gas distribution system atpoints at which objectionable condensation begins to occur. The locationof the burners may be influenced by many factors such as the length ofthe distribution system, the rate of heat loss from the gas flowingthrough the system, etc. While I have illustrated in Fig. 3 burnerslocated in the branch distribution mains leading from main l6 to theburners, it will be appreciated that if objectionable condensationoccurs in main l6, this main may be equipped with one or more burners atpoints where condensation begins to occur.

It will be noted this invention provides a process and apparatus forpreventing condensation of tarry matter from combustible gases, in gasdistribution systems, containing such matter by introducing into themains at suitable points hot gases in amount and at a temperaturesumcient to prevent lowering of the temperature of the gas below its dewpoint prior to reaching the burners. In accordance with my invention thegas as generated need not be washed and hence waste liquors which wouldpresent a dimcult disposal problem are not formed; and atof combustioninto said main in amount and at a temperature suflicient to prevent thetemperature of said combustible gas from falling below its dew pointduring flow through said main to its destination, means for feeding airto said burner, means for withdrawing a portion of the gas from saidmain and feeding, it to said burner, and means responsive to pressureconditions within said main for preventing flow of air and gas to saidburner when the pressure within the main falls below a predeterminedminimum.

2. Apparatus comprising in combination gas consuming appliances and agas distribution system including a gas main and branch lines forfeeding combustible gas containing condensable tarry constituents fromsaid main to said consuming appliances, means for preventing depositionof said constituents in said system comprising a burner communicatingwith each of said branch lines for producing hot products of combustion,means for mixing said products of combustion'with the gas flowingthrough said lines in amount and at a temperature to compensate for heatlosses from said combustible gas during its flow through saiddistribution system to said appliances, means including a valved conduitfor supplying air to the burner, means including a valved conduit forwithdrawing a portion of the combustible gas from said system andsupplying it to the burner, and means responsive to pressure conditionsin said system for automatically closing said gas and air valves whenthe pressure in said system falls below a predetermined minimum.

KARL KOLLER.

